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2.1 · Pelvic andLeg Arteries
113
2
according to the continuity equation) and the latter as 50%
stenosis (PSV ratio of 2). Angiographically, the degree of stenosis is 50% in both cases.
At the origin of the profunda femoris artery, angiography is additionally limited by the superposition of vessels.
Ultrasound is superior in this region when performed with
an adequate angle of insonation. In a study of 40 patients
who underwent thromboendarterectomy (TEA) for sonographically demonstrated high-grade stenosis of the
profunda femoris artery to improve collateralization of
supercial femoral occlusion, the high-grade stenosis demonstrated by ultrasound and conrmed intraoperatively was
identied denitely by angiography in only 85% of the cases,
and there was considerable interobserver variability in
stenosis grading.
Catheter-based digital subtraction angiography (DSA)
via a transfemoral or transbrachial approach can be regarded
as the gold standard on condition that views in two or three
planes are obtained and adequate opacication of the distal
arteries is ensured. Proper timing taking into account the
longer contrast agent transit time to the thigh and foot is
important to avoid misinterpretation.
angiography (MRA)
in evaluating the thigh and foot arteries in patients with
reduced contrast agent inow due to occlusive disease of
more proximal arteries (Fellner etal. 1999; Owen etal. 1992;
Kreitner etal. 2000). Several investigators demonstrated that
MRA allowed good evaluation of distal arteries, including
the pedal arch in patients with foot ischemia, and reliable
identication of patent runo vessels in cases where DSA did
not allow adequate evaluation for selection of a target artery
for pedal bypass graing (Dorweiler et al. 2002; Kreitner
etal. 2000).
For a complete evaluation of the lower extremity arteries,
an imaging modality optimized for visualization of the calf
and foot arteries
imaging test for evaluation of the iliofemoral arteries.
Noninvasive duplex ultrasound is ideal for the proximal leg
arteries and has the added advantage of providing highly
valid information on the ow eects of steno-occlusive
lesions of the iliac and femoropopliteal arteries. It is therefore
conceivable that a noninvasive diagnostic strategy combining (color) duplex ultrasound of the proximal leg arteries
with MRA of the calf and pedal arch may in the future replace
invasive DSA, which carries a number of risks (related to use
of contrast medium, radiation exposure, vascular puncture,
and catheterization).
e clinical usefulness of a diagnostic test depends not
only on its diagnostic accuracy and the relevance of the
results for therapeutic decision making but also on
ciently the examination can be performed
cally possible to perform a complete duplex scan from the
pelvic level down to the pedal arteries including identication of a target artery for bypass graing (which may require
administration of an echo enhancer, especially if a crural
bypass is contemplated). Few scientic data are available on
the time required for such an examination.
using dedicated coils is superior to DSA
needs to be supplemented by an additional
Magnetic resonance
how e-
. It is theoreti-
In a study performed by the author, 220 patients with
claudication, forefoot lesions, or rest pain were selected for a
duplex examination of the leg arteries on the basis of ABI
ndings. In this preselected population, duplex imaging
identied hemodynamically relevant stenosis or occlusion in
93% of cases. Using the above-described protocol
. Table 2.1), the examiner rst obtained and analyzed
(
Doppler waveforms from the groin at the junction of the
external iliac artery and common femoral artery (in comparison with the contralateral leg), followed by evaluation of
the profunda femoris origin and supercial femoral artery.
Next, spectral Doppler interrogation of the proximal and distal popliteal segments (P1 and P3) of the symptomatic leg
was performed. Only if spectral analysis or comparison of
the waveforms from the proximal and distal popliteal segments revealed any abnormalities or relevant changes was
the proximal arterial segment continuously mapped in the
B-mode with continuous spectral Doppler recording (longitudinal plane, sample volume slightly larger than the arterial
lumen). Occlusion length was determined taking into
account the sites of origin and entry of collaterals. With this
protocol, it took on average 5.2min to establish a diagnosis
and to decide on the therapeutic approach (conservative, surgery, PTA) and plan the surgical procedure (TEA or bypass
gra including selection of the distal recipient artery).
Patients with a long history of diabetes mellitus were not
included in this study because severe medial sclerosis with
acoustic shadowing makes the sonographic examination
more challenging and time- consuming.
is sonographic strategy allows reliable treatment decisions to be made, including selection of a bypass target artery
for surgical management of relevant stenosis or
patients with stage II PAOD and a patent popliteal artery
(. Table 2.20). In patients with stage III or IV disease and
occlusion at the pelvic or thigh level but a patent popliteal segment (from P1 to the tibiobular trunk), the inow obstruction above the popliteal artery is eliminated (PTA or bypass),
which can be done without examination of the calf arteries.
ey need to be included in the sonographic evaluation only
if the popliteal artery is stenosed or partially occluded and a
bypass onto a small artery below the knee is contemplated.
Examination of the arteries below the knee by ultrasound is
possible but time-consuming, as several authors have demonstrated (Boström et al. 2002; Hofmann et al. 2004).
Alternatively, angiography or MRA with dedicated coils can
be used. Angiography has several disadvantages including
invasiveness, contrast medium administration, and poor visualization of calf arteries in patients with long proximal occlusions. When duplex ultrasound is performed to identify a
bypass target below the knee, Doppler waveforms are obtained
from the dorsalis pedis and posterior tibial arteries at the
ankle level (and possibly also from the distal bular artery)
and are then compared with the waveforms from the P3 popliteal segment or proximal segments of the calf arteries. e
artery from which the proximal and distal waveforms are least
dierent is the most suitable target for the planned bypass and
should subsequently be mapped to conrm its suitability.
occlusion, in
114
Chapter 2 · Extremity Arteries
. Table 2.20 Sensitivities and specicities reported for color duplex ultrasound, contrast-enhanced magnetic resonance angiography
(CE-MRA), and computed tomography angiography (CTA) in patients with peripheral arterial occlusive disease (PAOD) using digital
subtraction angiography (DSA) as standard of reference
2
Study/
Meta-analysis
Patient
population
Color duplex CE-MRA CTA
Sensitivity (%) Specicity (%) Sensitivity (%) Specicity (%) Sensitivity (%) Specicity (%)
Nelemans
etal. (2000)
Lundin etal.
(2000)
Koelemay etal.
(2001)
Collins etal.
(2007)
While the studies listed in the table found slightly lower sensitivities for color duplex ultrasound, the method is comparable to DSA in
dening the therapeutic strategy in patients with PAOD (Collins etal. 2007; Koelemay etal. 1996)
Sonographic follow-up is useful to monitor the outcome
of vascular repair and identify gra stenosis, thus contributing to the timely initiation of therapeutic measures aimed at
maintaining gra patency (. Table2.16).
In patients with long-standing stenosis, extensive collat-
eral pathways
and altered hemodynamics in the main artery resulting from
PAOD, mostly
Fontaine stage II
PAOD, Fontaine
stage II
PAOD, mostly
Fontaine stage II
PAOD, mostly
Fontaine stage II
68–82 91–95 78–89 95–98 – –
72 97 81 92 – –
80–86 97 – – – –
80–98 89–99 92–99.5 64–99 89–99 83–97
may have developed. e reduced blood ow
vascular lesions– limits the communication of the ndings
to the surgeon or interventionalist. erefore, pretherapeutic
ultrasound is most valuable when performed by the radiologist or vascular surgeon who also treats the patient and benets from the additional hemodynamic information. e
diagnostic gain also depends on the skills of the examiner, as
ultrasound is highly
examiner-dependent.
a division of the blood volume between the collaterals and
the obstructed artery can lead to underestimation of stenosis
severity when only absolute PSV cutos are used for sonographic stenosis grading (see . Fig.2.16a).
Color duplex imaging with a high-resolution transducer
enables assessment of collaterals, in particular when the
occluded segment is short, and will detect stenosis at the reentry sites of collateral pathways (see . Fig. 2.63 (Atlas)).
Nevertheless, angiography is superior to ultrasound in providing a comprehensive overview of collateral circulation around
an occlusion. e hemodynamic situation distal to an occluded
segment can merely give hints. A relatively high PSV in conjunction with pulsatile ow in the postocclusive segment distal to the re-entry of collaterals suggests good collateralization.
PSV alone might lead to misinterpretation and is also increased
in diabetics with rigid arterial walls due to medial sclerosis.
When two or more sequential steno-occlusive lesions are
present, the more distal ones may be underestimated or difcult to assess, especially in patients with diabetic macroangiopathy. Moreover, the hemodynamic changes associated
with diabetic medial sclerosis and peripheral occlusions further impair stenosis grading by duplex ultrasound.
Angiographically, such sequential stenoses are identied by
their typical goose throat appearance.
When diagnostic ultrasonography and vascular repair are
performed by dierent persons or even by dierent departments, the lack of continuous documentation of the ndings – in particular in patients with complex patterns of
2.1.8.1 Comparison ofHemodynamic
andMorphologic Imaging Modalities
A systematic review of 48 studies investigating the accuracy
of dierent imaging modalities for detecting signicant arterial stenosis (>50%) in patients with symptomatic peripheral
arterial occlusive disease (PAOD) was presented by Collins
etal. (Collins etal. 2007). Compared with digital subtraction
angiography (DSA) as the gold standard, the results were as
follws: CT angiography (ve studies) had a median sensitivity of 97% (range, 89–100%) and a median specicity of
99.6% (range, 99–100%). Time-of-ight (TOF) magnetic
resonance imaging (four studies) had a median sensitivity of
86% (range, 77–100%) and a median specicity of 93.8%
(range, 85–98%). MRA using a gadolinium-based contrast
agent was found to have a median sensitivity of 94% (range,
85–100%) and a median specicity of 99.2% (range,
97–99.8%). Color duplex ultrasound (7 studies) had a similar
diagnostic performance with a median sensitivity of 90%
(range, 74–94%) and a median specicity of 99% (range,
89–100%). Duplex imaging and contrast-enhanced MRA
were found to have similar sensitivities and specicities of
approx. 90% (compared with DSA) in detecting hemodynamically signicant stenosis below the knee.
While CT and MRI are also considered noninvasive
imaging modalities, color duplex ultrasound is the least invasive method, causing few complications and no patient discomfort (. Table2.21).
2.1 · Pelvic andLeg Arteries
115
. Table 2.21 Validity, limitations, and cost of digital subtraction angiography (DSA), color duplex ultrasound, contrast-enhanced
magnetic resonance angiography (CE-MRA), and computed tomography angiography (CTA) in patients with peripheral arterial occlusive
disease (PAOD). Data are stratied by the segment involved and include diagnostic performance in the identication of wall structures and
extramural processes (Modied from Klein-Weigel etal. 2015)
2
Modality Aortoiliac PAOD Femoropopliteal PAOD Cruropedal PAOD Plaque morphology
and wall structure
DSA ++– +++ +++ ++– +++
Color duplex ++
CE-MRA +++ +++ ++
CTA +++ +++ ++– + ++ +++
Modality Degradation by mural
DSA +– ++ ++– +++ + ++ +++
Color duplex ++– +++ +++ ++ ++
CE-MRA – + + ++/+++
CTA +– ++ ++ + ++/+++
a
Diagnostic performance may be reduced in multilevel PAOD, depending on contrast ow selectivity and extent of arterial occlusion
b
Limited by vascular calcication, bowel gas, and obesity
c
High for identication of crural/pedal target for distal bypass
d
Often limited by superposition of veins
e
Limited by rather poor spatial resolution
g
Dependent on selectivity, protocol, and postprocessing
f
Largely dependent on extent of examination, patient-related factors, and technique used
b
calcication or plaque
+++ ++
Stent monitoring Examiner depen-
dence
a
c
d
+ –
++– +++ +++
e
+– ++
Time requirement Cost
f
g
g
Extramural
processes
+++
+
++
++
g
g
CTA involves high radiation exposure and the use of an
iodine-based contrast agent, and stenosis grading may be
impaired by calcied plaques or stent-related artifacts. e
quality of contrast-enhanced MRA depends on the use of
state-of-the-art equipment; general limitations include poor
visualization of below-knee arteries unless dedicated coils are
used, the susceptibility to artifacts, overestimation of stenosis
severity, and venous superimposition, which is most relevant
in the periphery. MRI is contraindicated in patients with
pacemakers or debrillators. Gadolinium-based contrast
agents should not be used in patients with impaired renal
function because they may induce life-threatening nephrogenic systemic brosis (Collins etal. 2007).
An experienced examiner is able to assess the arteries
below the knee throughout their course using a highresolution transducer. Extra time is required for the separate
evaluation of an occlusion or stenosis. What ultrasound fails
to provide is an overview of complex patterns of disturbed
perfusion with multiple occlusions of the lower leg arteries
that collateralize each other. In this situation, it is oen not
possible to adequately characterize peripheral outow.
Acoustic shadowing from calcied plaques may impair
the detection and grading of stenosis in small arteries. In
such cases, the sonographic search for a patent target artery
for a distal bypass is very time-consuming, especially when
the indirect stenosis criteria cannot be used due to proximal
occlusion or multilevel stenosis. Despite these limitations,
some investigators report accuracy rates for the detection of
steno-occlusive lesions below the knee that allow surgical
planning without prior angiography. According to these
studies, preoperative duplex ultrasound alone allows reliable
identication of a patent runo vessel for a planned bypass
gra below the femoropopliteal arteries. ese patients were
found to have the same intraoperative results as well as primary and secondary bypass patency and limb salvage rates as
patients undergoing preoperative angiography.
e studies
comparing duplex imaging with DSA in the
assessment of the cruropedal arteries report widely divergent
results (Karacagil etal. 1996; Koelemay etal. 1997) with sensitivities and specicities for the detection of occlusion ranging
from 50% to 90%. However, the investigators used 5 MHz
transducers, which are inadequate for the pedal vessels, and the
low resolution may explain the poor results. Other study groups
(Boström etal. 2002; Hofmann etal. 2001) describe limitations
of nonselective IA DSA in the visualization of the outow vessels of the foot (see . Fig.2.71 (Atlas)). In a consecutive series of
49 patients reported by Hofmann etal. (2001), the pedal arteries were poorly or not at all visualized by DSA in 32 cases
(65.3%). Based on the sonographic evaluation using a highresolution transducer (13 MHz), all 32 patients underwent
pedal bypass graing with a 2-year patency rate of 69.5%.
Boström et al. (2002) compared 157 vascular surgical procedures (32 inguinal TEA, 91 femoropopliteal bypass, 34 femorocrural bypass) performed solely on the basis of the ultrasound
116
Chapter 2 · Extremity Arteries
ndings and 172 procedures (28 inguinal TEA, 144 femoropopliteal and femorocrural bypass) planned on the basis of
angiography. e second group included patients with diagnos-
2
tically inadequate ultrasound examinations (in particular also
patients with femorobular bypass procedures). Cruropedal
bypass graing (ratio of 1:2 [ultrasound versus angiography
group]) and femorocrural bypass graing (ratio of 1:1) were
also performed using only the ultrasound ndings for planning. e primary patency rate of the bypass gras was 59% in
the ultrasound group versus 64% in the angiography group. In
98% of the patients examined by preoperative ultrasound alone,
no intraoperative revision of the planned procedure was necessary (not even on the basis of intraoperative DSA).
In conclusion, there is agreement that duplex ultrasound is
a valid method for the localization and grading of steno-
alone. e sonographic degree of stenosis is a function of its
hemodynamic relevance and is a better indicator of the
patient’s clinical status than estimating stenosis severity on the
basis of morphologic appearance alone (plaque). A timeecient ultrasound protocol based on spectral Doppler interrogation of representative sites and subsequent mapping only
of abnormal arterial segments allows sonographic evaluation
of each leg including treatment planning in less than 10min.
When treatment is planned on the basis of the ultra-
sound ndings
, the examination should ideally be performed by the surgeon or interventionalist treating the
patient. is has the added advantage that, during the examination, the physician can ask details about the patient’s pain
and other symptoms, explain the ndings, and discuss the
proposed therapy.
occlusive lesions in the iliac, femoral, and popliteal arteries
(. Table2.20) and that ultrasound alone provides all the information necessary for selecting the best treatment (medical
2.2 Arm Arteries
therapy, PTA, bypass graing) and for planning bypass procedures including identication of a suitable target vessel in this
2.2.1 Vascular Anatomy
territory (Boström etal. 2002; Alexander etal. 2002; Ascher
et al. 2004; Katsamouris et al. 2001; Lowery et al. 2007).
However, there is disagreement regarding its role in
guinal bypass grafting
, with some investigators considering
infrain-
preoperative ultrasound alone to be sucient (Hofmann etal.
2004; Boström etal. 2002; Mazzariol etal. 2000; Karacagil etal.
1996) and others recommending supplementary IA DSA
(Katsamouris etal. 2001). Several studies report comparable
infrainguinal bypass patency rates for procedures planned on
the basis of preoperative ultrasound versus those planned on
the basis of IA DSA (Collins etal. 2007; Koelemay etal. 1996).
Some authors conclude that supplementary preoperative IA
DSA does not add diagnostic information (Elsman etal. 1995;
Aly etal. 1998), not even in patients with complex reconstruction (crural/pedal) (Grassbaugh etal. 2003; Wong etal. 2013).
In a large study of 466 patients, Ascher etal. (2002) found pre-
e innominate artery (brachiocephalic trunk) arises from
the aortic arch on the right and, behind the sternoclavicular
joint, divides into the subclavian and common carotid arteries. On the le, the subclavian artery arises directly from the
aortic arch as does the common carotid artery at a more proximal site. Along its course, the subclavian artery rst gives o
the vertebral artery cranially. Further along the course, the
thyrocervical trunk arises, likewise from the posterior aspect,
and at once divides into a branch supplying the thyroid and
other branches supplying the skin and so tissue. Together
with the brachial plexus, the subclavian artery (. Fig.2.44)
passes through the scalene triangle (between the anterior and
medial scalene muscles and cranial to the rst rib) and arches
over the pleural dome, crossing under the clavicle, to continue
as the axillary artery. In individuals with a cervical rib, the
operative evaluation by color duplex ultrasound to be sucient for planning the bypass procedure in the majority of
cases with only 36 patients requiring a supplementary imaging
test (angiography, CTA, MRA).
sound
(CEUS) has not led to the expected improvement in
Contrast-enhanced ultra-
accuracy and stenosis grading. It may be helpful to identify a
bypass recipient artery below the knee in an occasional patient
with otherwise poor insonation conditions.
Velocity criteria (absolute PSV or PSV ratio) for identication and grading of stenosis need to be rened. e indiscriminate application of a single cuto, as in some studies,
does not take into account, for example, that normal blood
ow velocity is lower in the popliteal artery than in the femo-
Posterior
scalene
muscle
Brachial
plexus
Subclavian
artery
Middle
scalene
muscle
Anterior
scalene
muscle
ral artery or that PSV varies with plaque conguration and
the site at which prestenotic PSV for calculation of the PSV
ratio is measured.
When all factors aecting the hemodynamic situation
evaluated by duplex ultrasound are taken into account, inter-
ventional or surgical revascularization
(PTA, bypass gra) in
the iliacofemoropopliteal territory (including the P3 segment)
can be performed on the basis of the sonographic ndings
. Fig. 2.44 Course of the subclavian artery through the scalene tri-
angle. The subclavian artery runs between the rst rib, medial scalene
muscle, and anterior scalene muscle (from Heberer and van Dongen
1993)
palmar arch
ry
2.2 · Arm Arteries
117
2
subclavian artery is displaced cranially and anteriorly. Distal
to the thyrocervical trunk, the internal thoracic (mammary)
artery arises and descends behind the anterior chest wall and
about one ngerbreadth lateral to the sternum.
e branches of the axillary artery have extensive collateral connections to the branches of the subclavian artery and
supply the region of the shoulder girdle. e axillary artery
courses along the lower border of the pectoralis muscle
through the axilla and continues as the brachial artery. e
latter runs through the medial bicipital groove near the
humerus to the elbow and divides into the radial and ulnar
arteries at the level of the joint space. ere are anatomic
variants in which the radial artery arises from the brachial
artery in the upper arm (approx. 15%) or arises directly from
the distal axillary artery (1–3%). In approx. 1% of individuals, the ulnar artery also arises from the axillary artery.
e radial artery continues through the forearm on the
ulnar side of the radius to the wrist, where it unites with the
deep branch of the ulnar artery to form the deep palmar arch.
e radial artery primarily feeds the deep arch and the ulnar
artery the supercial arch. e main branches of the supercial arch give o the common palmar digital arteries, which
in turn give rise to the proper palmar digital arteries, the
main vessels supplying the ngers (
. Fig.2.45). A complete
connection between the supercial and deep palmar arches is
present in only approx. 80–90% of individuals.
Radial collateral
collateral artery
Radial recurrent
Radial
artery
Common interosseous
Brachioradial
interosseous artery
Radial
artery
Superficial
artery
Inferior ulnar
artery
artery
artery
Posterior
Superior ulnar
collateral artery
Ulnar recurrent
Recurrent interosseous
artery
Ulnar flexor of wrist
Anterior interosseous
Deep palmar arch
Common digital arteries
artery
Ulnar arte
Ulnar artery
Dorsal carpal
branch
artery
2.2.2 Examination Protocol andTechnique
e subclavian and axillary arteries are scanned at 5–7.5MHz
while a higher-frequency transducer can be used more distally, where the arteries lie closer to the surface. e nger
arteries are examined with a 7.5–10 MHz transducer.
Especially in the supraclavicular fossa, a curved array or sector transducer is better suited than a linear array transducer.
e subclavian and axillary arteries are best imaged in the
supine position with the examiner behind the patient’s head,
as for the examination of the carotid arteries. e forearm
and nger arteries are examined in the sitting patient with
the hand supinated.
e arm arteries are traced along their course from the
supraclavicular area to the palmar arch. In the upper arm, the
arteries are easily identied by B-mode scanning based on
sonoanatomic knowledge. Color duplex can be helpful in
identifying the vessels of the palmar arch and ngers. As elsewhere in the body, identication of a vessel is easier with the
transducer in transverse orientation. Spectral Doppler imaging is performed in longitudinal orientation using a smaller
angle of insonation.
e proximal portion of the subclavian artery is interrogated with the transducer in the supraclavicular position. In
evaluating the supra-aortic branches, the examiner should
pay special attention to the origin of the vertebral artery,
which must be dierentiated from the thyrocervical trunk.
Rhythmical tapping of the vertebral artery suboccipitally will
be transmitted and appear in the Doppler waveform from the
proximal segment of the artery.
e axillary artery is identied cranial to the axillary vein
with the transducer placed in the infraclavicular fossa and
followed along its path to the axilla (. Fig.2.46). e brachial
artery is examined in the upper arm from a medial position.
Depending on the clinical question to be answered, special attention must be paid to the presence of aneurysm or
stenosis of the subclavian artery. Inconclusive color duplex
Radialis indices
artery
. Fig. 2.45 Anatomy of the arm vessels
Proper digital
arteries
. Fig. 2.46 Transducer position for examination of the axillary artery
(transducer placed in the infraclavicular fossa) and subclavian artery
(course indicated by black line)
118
Chapter 2 · Extremity Arteries
ndings can be resolved by additional spectral Doppler evaluation. Under normal conditions, the subclavian, axillary,
and brachial arteries have a triphasic ow prole (high-
2
resistance ow of arteries supplying so tissue and skin).
e palmar arch and digital arteries are scanned using a
high-resolution probe (>10MHz), and a complete examination includes color duplex imaging and Doppler interrogation to dierentiate thromboembolic disease from vasospastic
conditions. A provocative test (heat and cold exposure) may
also be helpful for the dierential diagnosis.
2.2.3.2 Vascular Compression Syndromes
Various factors such as abnormal congenital bony and bromuscular structures and posttraumatic alterations (hyperostosis) are involved in the development of the thoracic outlet
syndrome. e nerves and vessels coursing through the narrow space of the upper thoracic aperture may become compressed, injured, or irritated when they have an atypical
course or when osseous or brous anomalies are present. e
clinical manifestation is very heterogeneous and varies with
the structure compressed. e vast majority of patients (97%)
suer from neurogenic symptoms due to compression of the
brachial plexus.
2.2.3 Clinical Role ofDuplex Ultrasound
e most common vascular symptoms are insidious epi-
sodes of microembolization that may lead to occlusion of the
2.2.3.1 Atherosclerosis
Stenoses of the upper extremity arteries chiey aect the
proximal subclavian arter
y and are four times more common in the longer le subclavian artery (especially at its origin from the aorta). If a subclavian stenosis or occlusion is
suspected, the sonographic evaluation should always include
the vertebral artery to identify ow reversal as a sign of the
subclavian steal syndrome. Prior to coronary bypass sur-
gery, color duplex ultrasound can serve to noninvasively
assess the internal thoracic artery as a candidate for graing.
Stenosis of the arm arteries distal to the subclavian artery is
rare and typically has no clinical relevance, except in patients
with a long history of diabetes mellitus or aer creation of a
hemodialysis access.
Repetitive trauma to the wrist can damage the distal ulnar
artery, which is particularly vulnerable as it passes over the
hook of hamate. Damage of the arterial wall can lead to the
formation of an aneurysm (. Fig.2.47), which may become
partially thrombosed and then embolize to the interdigital
arteries.
Besides atherosclerotic conditions and compression of
the subclavian arteries, vascular diseases of the upper extremity most commonly involve the nger arteries and palmar
interdigital arteries. Larger emboli, chiey arising from poststenotic arterial aneurysm (. Figs. 2.105 and 2.106 (both
Atlas)), may cause occlusion of the major arteries, namely the
ulnar, radial, and brachial arteries. e thoracic outlet syndrome predominantly occurs in patients aged 20–50 and
aects women at a ratio of 3:2.
Arterial compression syndromes of the thoracic outlet,
typically resulting from vascular compromise in certain arm
positions, are distinguished from the cervical rib syndrome,
which is caused by an accessory rib or a ligamentous or
brous band arising from the extra rib and ending freely or
attaching to the rst rib. e prevalence of cervical ribs is
reported to be 0.5–1%, but only 5–10% of aected individuals become symptomatic. e diagnosis is primarily radiological. Compression of the subclavian artery mainly occurs
at three sites where the artery courses through narrow ana-
tomic spaces
:
5 e anterior scalenus muscle gap (scalene triangle)
5 e narrow passage between the rst rib and clavicle
(costoclavicular space)
5 e narrow space below the pectoralis minor muscle at
its site of attachment to the coracoid process (pectoralis
minor space)
arch. e nger arteries can be aected by embolic occlusion,
vasculitis, and vasospastic conditions.
As already mentioned, several anatomic variations or pathologic processes can compromise these already narrow spaces,
resulting in mechanical irritation or compression of vessels
and nerves. Prolonged compression can lead to downstream
aneurysm formation with development of mural thrombi
and embolism of the arm arteries (see
. Figs.2.105 and 2.106
(both Atlas)).
Compression of neurovascular structures in one of
these passageways can cause pain, weakness in the arm and
hand, tingling nerve sensations, and other neurosensory
disorders or symptoms of vascular compression. Peripheral
embolism is the most common vascular complication of
thoracic outlet syndrome and is the presenting symptom in
50% of cases (Dunant 1980; Creutzig etal. 1988). Published
reports attribute a surprisingly high 70% of all emboli
involving the upper extremity to embolic complications of
the thoracic outlet syndrome. Most cases of embolism
. Fig. 2.47 Partially thrombosed aneurysm (AN) of the distal ulnar
artery
encountered in routine clinical practice are of cardiac
origin.
2.2 · Arm Arteries
119
2
e term thoracic outlet syndrome encompasses four
neurovascular syndromes distinguished according to the site
of vessel or nerve compression:
5 Scalenus anterior or cervical rib syndrome: In this
syndrome, the brachial plexus and the subclavian artery
are compressed due to thickening or an abnormal
position of the anterior or medial scalenus muscle at its
attachment to the rst rib, exostosis of the rst rib, or a
cervical rib. e subclavian vein is not involved as it
does not pass through the scalene triangle (. Figs.2.104,
2.105, and 2.106 (all Atlas)).
5 Costoclavicular syndrome: e narrow passage between
the clavicle and rst rib is the preferred site of venous
compression caused by a sagging shoulder girdle, rib
callus, or exostosis. e subclavian artery and the
brachial plexus are rarely compressed at this site (. Fig.
3.105
(Atlas)).
5 Hyperabduction syndrome: At the third site, mechani-
cal nerve damage predominates. It is due to compression
of the neurovascular bundle by the tendon of the
pectoralis minor muscle or the coracoid process when
the arms are stretched above the head (
(Atlas)).
5 Compression syndrome of the brachial artery: e
brachial artery passes beneath the bicipital aponeurosis
(lacertus brosus) in the hollow of the elbow and, in
individuals with well-developed biceps and brachial
muscles, can become compressed when the elbow is bent.
2.2.4 Documentation
Documentation of the ndings is the same as for the leg
arteries and comprises longitudinal B-scan views of the subclavian, axillary, and brachial arteries with the corresponding
Doppler waveforms obtained with angle correction. An
aneurysm is documented in two planes, and its diameter
measured in a transverse view. If stenosis is present, the
intrastenotic peak systolic velocity (PSV) measured with
angle correction is recorded. If no adequate Doppler waveform can be sampled from a central subclavian stenosis, the
monophasic waveform distal to the lesion is documented. In
patients with a vascular compression syndrome, documentation includes images showing the aected vessel in the compressed state.
2.2.5 Normal Findings
Like the leg arteries, healthy arm arteries show a triphasic
ow pattern with rapid forward ow reaching a peak during
systole, short reversal of ow during early diastole (due to
high peripheral resistance), and slow forward ow during
late diastole. Arterial diameters (6–7mm subclavian artery,
5–6mm axillary artery) and peak systolic velocities (PSV)
decrease toward the periphery (from 80–140 cm/s in the
proximal subclavian artery).
. Fig.2.107
2.2.6 Abnormal Findings, Duplex Ultrasound
Measurements, andClinical Role
2.2.6.1 Atherosclerosis
Due to the poor acoustic window in this anatomic region, the
diagnosis of a central subclavian stenosis typically relies on
indirect criteria with demonstration of monophasic and turbulent ow in the poststenotic segment. In patients with
good insonation conditions, the subclavian artery can be followed to its origin from the aorta with a low-frequency transducer, and a stenosis near the origin can be identied directly
by spectral Doppler interrogation with angle-corrected PSV
measurement.
As in the leg arteries, PSV in the subclavian and axillary
arteries shows wide interindividual variation in the normal
population. erefore, focal doubling of PSV is used to identify hemodynamically relevant stenosis. is criterion, however, is not applicable in the proximal subclavian artery and
brachiocephalic trunk, the preferred sites of arterial stenosis in
the arm. Here, a PSV greater than 2m/s is assumed to indicate
stenosis. e criteria of poststenotic ow in the leg arteries
(. Table2.9) can also be used to identify and evaluate stenoocclusive lesions in the arm arteries. However, the waveform
obtained downstream of an obstruction does not allow the
examiner to dierentiate high-grade stenosis from occlusion.
Color duplex ultrasound was reported to have 90% sen-
sitivity
and 99% specicity for identication of vascular
abnormalities in the proximal and middle segments of the
arm arteries compared with digital subtraction angiography
(Wittenberg et al. 1998). A surprisingly high sensitivity of
91% and specicity of 100% were found for the region near
the aortic arch, compared with 93% and 100% in the upper
arm and 88% and 98% in the lower arm.
In the nger arteries, the examiner must dierentiate atherosclerotic and embolic lesions from temporary vascoconstriction in Raynaud’s disease (see . Fig. 2.110 (Atlas)).
Examination with a high-resolution transducer (8–12MHz)
allows very accurate diagnosis of occlusion and stenosis.
Ladleif et al. (1998), for example, reported 86.9% sensitivity
and 93.8% specicity with a positive and negative predictive
value of 88.4% and 93%, respectively, compared with selective
hand angiography. A peripheral blood ow velocity<15cm/s
suggests upstream stenosis or occlusion. Overall, an ultrasound
examination of the nger arteries is very time-consuming.
Incidental ndings include arteriovenous malformation and
hemangioma.
Interdigital artery occlusion is suggested by the clinical
presentation and conrmed by duplex ultrasound. It may be
caused by cardiac disease or thoracic outlet syndrome.
Moreover, such occlusions may be due to the hypothenar
hammer syndrome
and the patient has a history of chronic repetitive blunt
trauma to the hypothenar region with secondary arterial wall
damage. When the latter is suspected (occupational history
of repetitive hand and wrist trauma and ischemia of the
fourth and h ngers), the examiner should look for an
aneurysmal dilatation of the distal ulnar artery (. Fig.2.47)
if they involve the ulnar artery territory
120
Chapter 2 · Extremity Arteries
in the hypothenar area. Ultrasonography depicts corkscrewlike changes already in early disease and demonstrates the
intra- aneurysmal thrombi responsible for embolization to
2
the interdigital arteries as well as the patent lumen in the
color duplex mode (see . Fig.2.109 (Atlas)).
hammer syndrome (see
compression in thoracic outlet syndrome may also give rise to
intraluminal thrombus formation. e specic type of thoracic outlet syndrome (. Fig.2.48) is diagnosed by ultrasonography of the respective sites of compression as suggested
. Fig. 2.109 (Atlas)). Intermittent
by the patient’s history and clinical symptoms using the fol-
2.2.6.2 Vascular Compression Syndromes
e wide variability of clinical presentations and the problem
of denitively conrming the thoracic outlet syndrome by
means of provocative maneuvers make it dicult to diagnose
this condition. A study in a German population revealed that
patients consulted an average of 6.5 specialists before the
syndrome was nally diagnosed– aer a mean of 4.3years
(Gruss etal. 1989; Gruss and Geissler 1997).
As already mentioned above, several neurovascular compression syndromes of the shoulder girdle need to be considered and dierentiated in patients presenting with hand
ischemia:
5 Cervical rib syndrome
5 Scalenus anterior syndrome (arterial: Adson test)
lowing provocative tests:
5 Adson test to identify arterial compression in the
scalene triangle: the hyperextended head is turned
toward the aected side (Schoop 1988) with the neck
muscles tensed and possibly with additional hyperabduction and rotation of the arm.
5 Costoclavicular or hyperabduction test to identify
venous compression in the costoclavicular space: gliding
of the clavicle over the rst rib with the arm hyperabducted narrows the passage, thereby inducing venous
compression. However, venous compression in this area is
more commonly caused by weak shoulder muscles, which
are better identied by a downward pull on the posteriorly
turned arm (with the shoulder drawn back, inspiration).
5 Scalenus minimus syndrome
5 Costoclavicular compression syndrome (venous:
hyperabduction test)
5 Pectoralis minor syndrome
5 Compression syndrome of the brachial artery
e
provocative maneuver is performed with spectral
Doppler sampling
at the target site (. Fig.2.48) or, if this region
cannot be interrogated, distal to it. e test is positive if there is
ow acceleration in the compressed artery or if an altered ow
prole is obtained distal to the compressed segment. e exam-
Diagnostic workup should begin with a
including determination of pulses, auscultation, and bilateral
Doppler blood pressure measurement. Unilateral pulse
reduction or obliteration with elevation or abduction of the
arm is not a very specic symptom and is seen in 30–60% of
young adults without symptoms related to thoracic outlet
syndrome. is test merely shows intermittent subclavian
artery compression, and a positive test is not diagnostic of a
clinically relevant vascular compression syndrome. A clinically more relevant test to reproduce the symptoms of thoracic outlet syndrome is the ninety degree abduction in
external rotation (90° AER) test: with the arms in this position, the patient is instructed to make a st every 2–3s for
3min. Most patients will experience fatigue, pain, and heaviness before the end of the 3-min test period. Formication
suggests compression of the upper plexus. Additional pain
and pallor of the ngers indicate arterial compression.
e diagnosis of thoracic outlet syndrome further
requires measurement of the
nerve conduction velocity of
the ulnar and median nerves. Diminished nerve conduction
velocity suggests brachial plexus compression, but normal
nerve conduction velocity does not rule out thoracic outlet
syndrome. Nerve conduction velocities above 65 m/s are
normal and velocities below 45m/s indicate brachial plexus
compression (Urschel 1976).
When (color) duplex conrms interdigital artery occlusion, the examiner proceeds to identify the source of embolism, primarily a partially thrombosed aneurysm. Such
aneurysms typically develop secondary to compressioninduced wall damage in thoracic outlet syndrome or as a result
of traumatic damage to the distal ulnar artery in hypothenar
clinical examination
iner can also move the transducer toward the compressed segment from the periphery, intermittently recording spectral
Doppler information. Provocative tests are necessary to diagnose the specic type of compression syndrome and initiate
proper treatment, as all of them are rare and the clinical symptoms are oen nonspecic. (. Table2.22). If there is occlusion
of the forearm or nger arteries, it is crucial to identify the
source of embolism. e search should focus on the possibility
of a partially thrombosed aneurysm of the subclavian artery,
which typically develops on the basis of a scalene muscle or cervical rib syndrome. In rare cases, emboli may arise from thrombotic deposits of the damaged wall of the axillary artery in
hyperabduction syndrome. ese changes are caused by intermittent compression of the axillary artery and will be identied
with the transducer placed in the axilla (see
. Fig.2.107 (Atlas)).
Patients with venous compression and clinical symptoms
should initially be treated by physical therapy to strengthen
the shoulder muscles or by resection if bony abnormalities
such as a cervical rib or exostosis are present.
In thoracic outlet syndrome with compression or
mechanical irritation of the arteries or brachial plexus, the
rst rib should be resected before secondary damage to the
vessel wall with development of aneurysm occurs. If secondary damage has already occurred, the aected arterial segments must be resected as well.
e management of patients with thoracic outlet syndrome is prevention-oriented, meaning that the goal is to
intervene before compression-related complications such as
vascular damage, poststenotic aneurysm, or embolism occur.
When a combination of the Adson test with hyperabduction
of the arm is performed in normal young individuals, 30%
ab
2.2 · Arm Arteries
121
2
c
e
. Fig. 2.48a–e Thoracic outlet syndrome caused by exostosis in a patient with a history of clavicular fracture (cl). In the costoclavicular space,
compression of the vein is more common than compression of the artery, unless exostosis secondary to fracture is the underlying mechanism.
a In a relaxed position with the arms at the side, the axillary artery distal to the costoclavicular space shows normal triphasic ow with a peak
systolic velocity (PSV) of 100cm/s (waveform obtained with transducer in infraclavicular fossa). b With beginning hyperabduction, ow shows
increasing signs of stenosis with aliasing in the color ow image and a PSV of 400cm/s. c With extreme hyperabduction, the clavicular exostosis
(cl) completely compresses the axillary artery, seen as absence of ow distally. d With the arms at the side (corresponding to a), there is normal
triphasic ow in the subclavian artery. e With hyperabduction, a knocking waveform is obtained from the subclavian artery (prestenotic segment
upstream of the exostosis) as a sign of downstream obstruction
d
will show compression with temporary stenosis of the subclavian artery. Even with these test results, most of them do not
develop compression-related complications, and no treatment
is warranted. e problem is to identify those individuals in
whom the vascular compression that can be reproduced with
this provocative maneuver will lead to the rare thoracic outlet
syndrome with the above-described vascular complications.
Patients with thoracic outlet syndrome typically do not
seek medical attention until vascular complications have
developed. In most patients with complications of thoracic
122
Chapter 2 · Extremity Arteries
. Table 2.22 Duplex ultrasound diagnosis of thoracic outlet
syndrome in 680 patients presenting with clinical symptoms of
arterial/venous compression of the upper extremity (patients
2
seen from 1991 through 2001; diagnosis conrmed by angiography/venography, intraoperative ndings)
Type of thoracic outlet syndrome Number
Cervical rib syndrome (arterial) 3
Scalenus anterior syndrome (arterial)
– With poststenotic aneurysm
Costoclavicular compression syndrome (venous)
– With venous thrombosis
Pectoralis minor syndrome (arterial) 2
6
2
8
5
characteristic morphologic changes including assessment of
the hemodynamic relevance of luminal narrowing (see
5.8.2
) and monitoring of the therapeutic response (. Fig.2.49).
2.2.6.4 Buerger’s Disease
7 Sect.
romboangiitis obliterans (Buerger’s disease) of the upper
extremity is characterized by multiple segmental occlusions of
the palmar and digital arteries. e disease predominantly
occurs in men and usually presents before age 40. It is rare in
Europe, accounting for 0.5% of all cases of peripheral arterial
occlusive disease. In most cases, the occluded arteries show no
atherosclerotic lesions. Concomitant thrombophlebitis is common. Ultrasound will typically reveal multiple occlusive lesions
characterized by low echogenicity and absence of plaque deposits (skip lesions). e vessel diameter of aected segments may
be reduced. Chronic disease is characterized by recanalization
outlet syndrome seen by the author, even retrospective analysis of their histories revealed no prior signs or symptoms that
might have pointed to the diagnosis.
and the presence of corkscrew collaterals around occluded seg-
ments (see . Fig.2.32). At this stage, aected arterial segments
appear inhomogeneous on B-mode images, while color ow
images depict thin, tortuous collaterals extending beyond the
2.2.6.3 Vascular Inammatory Disease
Inammatory disease, such as Takayasu’s arteritis (1–3/million/year), is a rare cause of upper extremity ischemia. e
normal diameter of the artery. Collaterals around occlusions are
supplied by intact arterial segments (known as Martorell’s sign)
or by the vasa vasorum of the occluded segment.
arm arteries (subclavian and axillary arteries) are a preferred
site of giant cell arteritis, a rare vasulitis primarily aecting the
aorta and its primary branches. Rare sites are the pelvic, visceral, coronary, renal, and common carotid arteries. Early differentiation from atherosclerotic steno-occlusive disease is
critical for adequate therapeutic management. Timely initiation of cortisone therapy is crucial in autoimmune granulomatous arteritis and is also a prerequisite for successful
vascular reconstruction. Without prior or concomitant cortisone treatment, reconstructive measures have a poor outcome,
and the risk of early recurrence is high. Most patients responding well to cortisone and showing resolution of inammatory
wall thickening do not require additional vascular repair.
Sonographic demonstration of a thickened vascular wall
(>1mm) with circumferential luminal narrowing of a longer
segment than in atherosclerotic stenosis points to an inammatory process. Wall thickening >1.5mm is pathognomonic of
vasculitis (Schmidt etal. 2008). e thickened wall is of low,
homogeneous echogenicity and clearly demarcated from the
lumen while an atherosclerotic vessel wall has higher echogenicity and appears inhomogeneous. Duplex ultrasound is the
diagnostic modality of choice, allowing identication of the
2.2.6.5 Raynaud’s Disease
Raynaud’s disease manifests as episodes of vasospasms of the
ngers and toes
. A primary or idiopathic form is distinguished from secondary Raynaud’s disease, which is oen
related to connective tissue diseases or other underlying causes.
e episodes are typically triggered by cold or stress
and manifest as classic tricolor changes of rst white (pallor), then blue (cyanosis), and then red (reperfusion hyperemia). is is known as the tricolor sign and allows the
diagnosis of Raynaud’s disease to be made on the basis of
the patient’s clinical presentation. e primary role of
duplex ultrasound is to dierentiate Raynaud’s disease
from other vascular conditions (see . Fig. 2.110 (Atlas))
based on their specic morphologic and hemodynamic
changes. Placing the hand in warm water (37°C) during the
examination will relieve the vasospasm, allowing dierentiation of Raynaud’s phenomenon from xed vascular
occlusion. Supplementary tests to rule out morphologic
and structural perfusion disorders of the hands and feet
include digital photopletysmography and pulse contour
analysis (
7 Sect. 2.1.6.4.6).